Editing AMPA receptor (section)

====AMPA receptor trafficking to the PSD in response to LTP====
Once AMPA receptors are transported to the perisynaptic region through PKA or SAP97 phosphorylation, receptors are then trafficked to the [[postsynaptic density]] (PSD). However, this process of trafficking to the PSD still remains controversial. One possibility is that, during LTP, there is lateral movement of AMPA receptors from perisynaptic sites directly to the PSD.<ref name="Borgdorff Choquet 2002"/>  Another possibility is that [[exocytosis]] of intracellular vesicles is responsible for AMPA trafficking to the PSD directly.<ref name="pmid15448273">{{cite journal | vauthors = Park M, Penick EC, Edwards JG, Kauer JA, Ehlers MD | title = Recycling endosomes supply AMPA receptors for LTP | journal = Science | volume = 305 | issue = 5692 | pages = 1972–5 | date = September 2004 | pmid = 15448273 | doi = 10.1126/science.1102026 | bibcode = 2004Sci...305.1972P | s2cid = 34651431 }}</ref> Recent evidence suggests that both of these processes are happening after an LTP stimulus; however, only the lateral movement of AMPA receptors from the perisynaptic region enhances the number of AMPA receptors at the PSD.<ref name="pmid19914186">{{cite journal | vauthors = Makino H, Malinow R | title = AMPA receptor incorporation into synapses during LTP: the role of lateral movement and exocytosis | journal = Neuron | volume = 64 | issue = 3 | pages = 381–90 | date = November 2009 | pmid = 19914186 | pmc = 2999463 | doi = 10.1016/j.neuron.2009.08.035 }}</ref> The exact mechanism responsible for lateral movement of AMPA receptors to the PSD remains to be discovered; however, research has discovered several essential proteins for AMPA receptor trafficking. For example, overexpression of SAP97 leads to increased AMPA receptor trafficking to [[synapses]].<ref name="pmid20133708">{{cite journal | vauthors = Howard MA, Elias GM, Elias LA, Swat W, Nicoll RA | title = The role of SAP97 in synaptic glutamate receptor dynamics | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 107 | issue = 8 | pages = 3805–10 | date = February 2010 | pmid = 20133708 | pmc = 2840522 | doi = 10.1073/pnas.0914422107 | bibcode = 2010PNAS..107.3805H | doi-access = free }}</ref> In addition to influencing synaptic localization, SAP97 has also been found to influence AMPA receptor conductance in response to [[glutamate]].<ref name="pmid19357261">{{cite journal | vauthors = Waites CL, Specht CG, Härtel K, Leal-Ortiz S, Genoux D, Li D, Drisdel RC, Jeyifous O, Cheyne JE, Green WN, Montgomery JM, Garner CC | display-authors = 6 | title = Synaptic SAP97 isoforms regulate AMPA receptor dynamics and access to presynaptic glutamate | journal = The Journal of Neuroscience | volume = 29 | issue = 14 | pages = 4332–45 | date = April 2009 | pmid = 19357261 | pmc = 3230533 | doi = 10.1523/JNEUROSCI.4431-08.2009 }}</ref> [[Myosin]] proteins are calcium sensitive motor proteins that have also been found to be essential for AMPA receptor trafficking. Disruption of myosin Vb interaction with Rab11 and Rab11-FIP2 blocks spine growth and AMPA receptor trafficking.<ref name="pmid18984164">{{cite journal | vauthors = Wang Z, Edwards JG, Riley N, Provance DW, Karcher R, Li XD, Davison IG, Ikebe M, Mercer JA, Kauer JA, Ehlers MD | display-authors = 6 | title = Myosin Vb mobilizes recycling endosomes and AMPA receptors for postsynaptic plasticity | journal = Cell | volume = 135 | issue = 3 | pages = 535–48 | date = October 2008 | pmid = 18984164 | pmc = 2585749 | doi = 10.1016/j.cell.2008.09.057 }}</ref> Therefore, it is possible that myosin may drive the lateral movement of AMPA receptors in the perisynaptic region to the PSD. Transmembrane AMPA receptor regulatory proteins (TARPs) are a family protein that associate with AMPA receptors and control their trafficking and conductance.<ref name="pmid16513974">{{cite journal | vauthors = Nicoll RA, Tomita S, Bredt DS | title = Auxiliary subunits assist AMPA-type glutamate receptors | journal = Science | volume = 311 | issue = 5765 | pages = 1253–6 | date = March 2006 | pmid = 16513974 | doi = 10.1126/science.1123339 | bibcode = 2006Sci...311.1253N | s2cid = 40782882 }}</ref> [[CACNG2]] (Stargazin) is one such protein and is found to bind AMPA receptors in the perisynaptic and postsynaptic regions.<ref name="pmid12771129">{{cite journal | vauthors = Tomita S, Chen L, Kawasaki Y, Petralia RS, Wenthold RJ, Nicoll RA, Bredt DS | title = Functional studies and distribution define a family of transmembrane AMPA receptor regulatory proteins | journal = The Journal of Cell Biology | volume = 161 | issue = 4 | pages = 805–16 | date = May 2003 | pmid = 12771129 | pmc = 2199354 | doi = 10.1083/jcb.200212116 }}</ref> The role of stargazin in trafficking between the perisynaptic and postsynaptic regions remains unclear; however, stargazin is essential for immobilizing AMPA receptors in the PSD by interacting with PSD-95.<ref name="pmid11140673">{{cite journal | vauthors = Chen L, Chetkovich DM, Petralia RS, Sweeney NT, Kawasaki Y, Wenthold RJ, Bredt DS, Nicoll RA | display-authors = 6 | title = Stargazin regulates synaptic targeting of AMPA receptors by two distinct mechanisms | journal = Nature | volume = 408 | issue = 6815 | pages = 936–43 | year = 2000 | pmid = 11140673 | doi = 10.1038/35050030 | bibcode = 2000Natur.408..936C | s2cid = 4427689 }}</ref> PSD-95 stabilizes AMPA receptors to the synapse and disruption of the stargazin-PSD-95 interaction suppressed synaptic transmission.<ref name="pmid17329211"/>